Pneumatic control



I Ap 21, 1942- s. w. NICKELLS 2,280,345

PNEUMATI-C CONTROL Filed March 13, 1939 4 Sheets- Sheet l Fig. 1

I TO tQNl'ROLLER TO AIR: SUPPL Siunley w. Nickel 1,1

A ril 21, 1942.

s. w. NICKELLS PNEUMATIC CONTROL Filed March 13, 1959 4 Sheets-Sheet 3 @IH. 1 x m m 2 O F 2 2 W W m w g m w m u m e r A H .l m m m w/ 4 I .m nlhrlwliuq t m I) A m m F0. 6 NNP\\\\\\\\\\\\E m :FES l 2 n\ M F m H m 2 SUPPLY TO MOTOR SWITCH LINE 'April 21, 1942.

s. w. NICKELLS PNEUMATIC CONTROL Filed Ma rch 13, 1959 4 Sheets-Sheet 4 Ill ilflnentoi Slanles N'i cKel 1 s thermostat;

Patented Apr. 21, 1942.

' UNITED STATE PNEUMATIC CONTROL Stanley W. Nickells, Chicago, Ill., assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application March 13, 1939, Serial No. 261,672

14 Claims.

This invention relates in general to automatic controls and more particularly to automatic controls of the pneumatic or pressure actuated type.

Itis an object of this invention to provide a pneumatic or pressure actuated control device'of the non-leaking type which employs a pair of valves which control the flow of fluid to and from a valvechamber, these valves being controlled by a lever, the device being simple and rugged in construction, having a low reversal loss, and being adapted to form the basis of a plurality of types of controls. I e

A further object of this invention is to. provide a device of the type mentioned in which'the lever which actuates the valves has its axis of rotation located between the valves and in which the lever actuates the valves through a sealing diaphragm which forms one wall of a chamber common to both valves. A still further object is the provision of a device of this type in which a single diaphragm acts to actuate the lever and as the seal.

Another object of this invention is the provision of a controlling device for positively control ling the position of a pressure actuated motor.

Still another object of this invention is the provision of a device formed as mentioned above for variably controlling fluid pressure and which is adjustable manually or automatically, to thereby provide a non-leaking type controller.

A further object of this invention is the provision of a snap acting three-way or diverting valve utilizing the arrangement mentioned above.

Other objects will appear from the following description and the appended claims.

For a full disclosure of this invention, reference is made to the following detailed description and accompanying drawings, in whichusual diaphragm as well known in the art. The

diaphragm actuates a push rod 3 which is pivoted to an operating lever 4, this lever in turn being pivoted to a bracket 5 which is secured to the top of the diaphragm casing. A spring '6 is secured to the lever 4 and also to the base 1 of casing 2 and this spring serves to bias the lever arm 4 in a direction tending to collapse the diaphragm of the motor. The motor l is also shown as having a bracket 8 secured to the top of the casing l and carryingan adjustable stop screw 9 which serves to limit the movement of lever 4 in the upward direction. Damper motors ofthis type are well known in the art and form no part of this invention.

In order to positively control the position assumed by the lever arm 4, I have provided the positive positioning device generally indicated at III. This device is mounted directly upon the top of the diaphragm casing to one side of the push rod 3. Referringnow to Figures 3, 4, and 5, this positive positioner consists of a base member II which is secured to the motor diaphragm casing by means of ears l2. This base member is formed to provide a diaphragm chamber l3 and also is provided with bores 14 and 15 which communicate with smaller bores l6 and H which form valve ports communicating with a valve chamber I8 which is also formed in the base member.

f Cooperating with valve ports 16 and H are valve Figure 1 shows the application of the positive positioner to a damper motor;-

Figure la is a detail of the spring adjusting arrangement;

Figure-2 shows a pneumatic valve having the positive positioner applied thereto;

Figure 3 is .a plan view of the positive positioner with the cover removed;

v Figure 4 is'a sectional elevation of the positive positioner; v

Figure 5 is an end view of the positive positioner; g

Figure 6 is a sideview. partly in section of the invention applied to a non-bleed type pneumatic 'inFigure 6;

members 19 and 20 having guide portions 2| and 22 which fit into suitable hollow'plugs 23 and 24 which cover the lower ends of the bores I4 and I5. Provided between the valve members and the plugs are suitable springs for biasing the valve members against the valve ports. The valve members l9 and 20 are also provided with upwardly extending portions 25 and 26 which extend through the valve ports into engagement with a diaphragm 21. This diaphragm may be formed of any suitable material such as leather or rubber and preferably is made of a material known as Neoprene. It will be noted that this diaphragm -2| covers the entire base portion including the diaphragm chamber 13 and the valve chamber 18 and is held in place by means of a cover plate 28, this cover plate having an opening 29 which coincides with the diaphragm chamber 13 and openings and 3| which are above the valves l9 and 28. This cover plate may be secured to the base portion H in any suitable manner such as by screws Reference character 34 indicates an operating and 33.

lever having .a depending portion which is pivotally secured to thecover plate 28 at 33 which point it will be noted is mid way between the valve members l9 and 20. The lever 34 is provided with an adjustable screw 31 which extends through the opening 29 into engagement with above the valve extensions 25 and 26. The adjusting screws 40 and 4| are adjusted so'that when the lever 34 is in' intermediate position, both valves |9 and 20 engage their respective valve ports or seats. Upon clockwise rockingof the lever from this intermediate or neutral position, the valve member 20 will be disengaged fromits seat while the valve member |9 will remain engaged with its seatr Upon, rocking of the lever 34 in the counter-clockwise direction from this intermediate position, the valve port will remain closed while the valve member I9 will be shifted from its seat: The adjusting screws 31, 40 and 4| may be held in their ad? justed position in any suitable manner such as by lock nuts or by a spring such as 42 which is bent so as to engage each screw and frictionally hold each screw in its adjusted position.

The cover plate 28 is provided with a recess 43 which receivesa spring 44 which. is also received ina recessed portion of the valve lever 34. This spring servesto, bias the valve lever in a counter-clockwise direction, thereby tending to hold the diaphragm portion 38 in downward position. The lever arm 34 is also provided with an extension 45 which extends through a suitable opening 46 in the cover 41.

Referring now to Figure 1, the lever extension 45 is provided with a number of holes 48 which are adapted to receive a spring 49. The upper end of this spring is supported by a pin 50 which is carried by a collar 5| which surrounds the motor lever arm 4 and is secured in fixed position by'means of a lock screw 52 (Figure la). The collar 5| isprovided with openings 53 and 54 which receive the downwardly ,extending portion of pin 50. It will be apparent that by loosening lock screw 52, the' collar 5| may he slid along the lever arm 4 and also the pin 50 may be moved upwardly or downwardly to thereby vary the tension of the spring 49.

Referring again to Figures 3, 4, and 5, the base portion II is provided with a bore 55 which is formed to receive a suitable pipe, and this-bore 55 communicates through a passage 56 with the valve chamber |8. This passage 55 is connected by a pipe 51 to the diaphragm of the damper motoi' (Figure 1). The valve chamber I8 is therefore in direct communication with the diaphragm of the motor. The base member I is also provided with a bore 58 which is adapted to receive an air supply pipe and which communir cates with the valve bore l5 through a passage 59. Air under pressure is therefore supplied to the space beneath the valve member 20. The valve bore |4- communicates through a passage 8] with atmosphere. It will therefore be seen that the valve member l9 controls the exhaust of air from the valve chamber l8 and the motor diaphragm, while the valve member 28 controls the supply of air to the motor diaphragm.

The base member II is also provided with a bore 6| which is adapted to receive the control line from the controller which controls the motor position. For example, if the damper motor is controlled by a thermostat, the thermostat is connected to the positioner at this point. As shown, the bore 6| communicates with the diaphragm chamber l3 and thus the damper motor controller acts to vary the pressure applied to the diaphragm portion 38.

From the foregoing description, it will be apparent that the lever arm 34 is biased in the counter-clockwise direction by the spring 49 and is urged in the clockwise direction by the diaphragm portion 38. The diaphragm portion 38 20 thus opposes the action of the spring 49. When the tension of spring 49 just balances the pressure under diaphragm portion 38, the lever arm 34 will assume the intermediate or neutral position in which both the supply valve and the exhaust valve are closed and consequently the motor will remain stationary.

If the controller for the damper motor increases the pressure applied to diaphragm chamber l3, the upward force against diaphragm portion 38 will overcome the tension of spring 43 and thus'rock lever'arm 34 in the clockwise direction, thereby causing the screw 4| to urge the valve member 20 downwardly, thus permitting air under pressure to flow into the valve chamber I8 and through pipe 51 into the motordiaphragm which causes this diaphragm to expand and rotate the lever arm 4 in the counter-clockwise direction against the action of spring 8. As the lever arm 4 rotates in this direction, the tension of spring 49 will be increased, thereby tending to return the valve lever 34 to, intermediate position; When the motor position just corresponds to the new pressure applied to diaphragm chamber |3 by the controller, the lever arm 34 will be returned to its initial position thereby causing the air supply valve to close for maintaining the motor stationary. Due to this positive supply of air'to the motor until it reaches the correct position, the lever arm 4 will be caused to assume the exact position called for by the controller irrespective of the load upon the device controlled and friction.

If the motor controller reduces the pressure applied to the diaphragm chamber I3, the tension of the spring 49 will now overcome the upward force against diaphragm 38 and thus rock the valve lever 34 in a direction to open the vent valve I9. This will permit escape of air I from the motor diaphragm and thus permit the spring 6 to cause rotation of the lever arm 4 in the clockwise direction. This mo ement of thelever arm 4 will reduce the tension of spring 49, thereby tending to return the lever arm 34 to the neutral or intermediate position. It will now be apparent that when the motor assumes the position required by the controller, the lever arm 34 will assume the neutral position for closing the vent valve |9.-

It should be notedthat due to the particular valve actuating arrangement utilized in which the valves are actuated through the sealing diaphragmand in which the valve lever arm is pivoted equidistant between the two valve members, frictional losses in the device are reduced to a minimum. Also, due to the pivoting of the valve lever equidistant-between the valve members, the portion of the diaphragm covering the valve chamber I8 acts equally and oppositely upon the screws 40 and 4|. This completely neutralizes the effect of changes in pressure within the valve chamber I8. This arrangement has proved very satisfactory in practice and it has been found that the device will operate to change the motor position on a change in applied pressure of only one-twentieth of a pound per square inch or less.

It should be noted that by adjusting the position of spring 49 on the extension 45 and the lever 4, the eifect of the movement of lever arm 4 upon the tension of spring 49 and its effect upon the valve lever 34 may readily be varied. Thus if the spring 49 is shifted to the right on lever 4 and extension 45, the spring .will be extended a greater amount for a given movement of lever arm 4 than occurs in the position shown. Consequently, there will be a greater change in spring tension for a given motor travel and thus for a given change in pressure applied to the diaphragm chamber I3, there will be a smaller amount of motor travel. This simple adjusting means permits the motor action to be easily varied to suit the particular sequence of-operation desired for a given installation. By adjusting the position of pin 50, the initial spring tension may be varied. It will be apparent that this initial tension of spring 49 .plus the force of spring 44 determines the minimum pressurewhich must be applied to the diaphragm chamber I3- in order to cause the lever arm 4 to begin travelling from its clockwise limit of rotation.

parent that this invention provides a very simple, rugged and sensitive controller which is adaptable to different types of pneumatic motors'and which can be readily adjusted to provide the desired sequence of operation for the motor to which'it is applied. While theapplication of pressure to the dia hragmportion 38 is shown as being controlled by a pneumatic controller, the invention is not limited to this arrangement. If desired, the diaphragm chamber may be connected by a capillary tube to a control bulb at a a desired location, and a volatile fluid provided for changing the pressure applied to the diaphragm with changes in temperature at the bulb.

Referring now to Figures 6 and 7, these figures illustrate the application of the improved diaphragm valve actuating assembly which is utilized in the positive positioner, to a thermostat of the non-bleed type. Reference character 90 indicates a base portion of the thermostat, this base portion being provided with a diaphragm chamber 9| and another diaphragm chamber 92.

' This base portion is also provided with bores Referring to Figure 2, this figure shows theapplication of the same positive positioner to a pneumatically actuated valve. The valve I0 illustrated is of usual form including a valve cas- 'ing. II upon which is mounted the usual dia-- phragm cage I2 containing the actuating diaphragm which operates the valve stem I3, the diaphragm being biased upwardly by a spring I4. In this case, the positioner I0 is mounted upon the side of the diaphragm cage and is connected to the diaphragm by means of pipe I5 which corresponds to the pipe 51 of Figure 1. When the positioner is applied to a valve, the lever arm extension of the valve lever 34 is discarded and in its place an extension 11 is attached to the valve lever, this extension extending through an opening I8 in the cover member 41 (Figure 3). This extension I1 supports a collar I9, this collar being adjustably secured thereto by a lockscrew 00 and supporting the positioner spring 0| corresponding to spring 49 o f'Figure 1. The lower end of spring 9| is attached to a link 82 which is in turn secured to a follow-up member 83 mounted in any suitable manner upon the motor diaphragm so as to move with the valve stem 19. The link 02 may be secured to the-follow-up member 83 by means of nuts 84 which permit adjusting of the link axially of member 83 and also permit vertical adjustment of this link for varying the initial spring tension. It will be apparent that by. adjusting the collar 80 and the link 82 axially of extension 11 and member 93, the valve movement for a given change in applied pressure may be readily adjusted, and that by adjusting the link 82 upwardly and downwardly the tension of spring BI may be varied so as to determine the pressure at which movement'of the valve begins.

From the foregoing description, it will be ap- 75 93 and 94 which communicate with valve chambers 95 and 96, respectively, through valve ports as shown. The chambers 95 and 96 communicate with each other through a passage 91 and communicate through a passage 90 with the diaphragm chamber 9|. The bores 93 and 94 are provided with valve members 99 and I00, and these valve members are urged against their seats by m ans of springs and are provided with guides extending into plugs IM and I02, this valve arrangement being the same as shown in Figure 4. The valve bore 93 communicates through a passage I03 with an air supply pipe I04. Therefore, the valve member 99 is an air supply valve. The valve bore 94 communicates with atmosphere througha port I05 in plug I02. Consequently, the valve member I00 is a vent valve. The supply and vent valves 99 and I00 are actuated through the diaphragm I06 which covers the diaphragm chambers 9| and 92 as well as the valve chambers 95 and 96, by means of adjustable screws I01 and I08 which are carried by a valve lever arm I09 which is pivoted at IIO intermediate the valve members. The arm I09 also carries an adjusting screw III which abuts the portion II2 of the diaphragm covering diaphragm chamber 9 I. is substantially the same as shown in Figure 4. In this case, however, a spring II 3is located within the diaphragm chamber 9| for urging the diaphragm portion I I2 outwardly thereby biasing the lever arm I09 in a direction tending-to open the vent valve I00.

Also pivoted at H0 is a bracket I I4 which carries an extension II5 to which is secured a bimetallic element IIG. This bimetallic element is provided with a slot'I IT for receiving an adjustable abutment member II9 having a pin II 9 which engages the lever arm I09. For illustrative purposes, the bimetallic element I0! maybe considered as warping to the left upon increase in temperature while warping to the right upon temperature decrease.

' Attached to an extension I20 of the base portion is a. shaft; I2I carrying a night adjusting cam I22. This shaft I2I is provided with an adjusting knob I23. Also mounted upon the shaft I2I is a day adjusting cam I24 which is rotated by an adjusting knob I25. The extension II5 which carries the thermostatic element H6 is provided with a portion I20 which extends into the space between the cams I22 and I24 and is The arrangement thus far described urged against the cam I24 by means of a spring I21..* It will be apparent that when the portion I26 engages the cam I24 the position of member 5 and thus the thermostatic element I I6 can readily be adjusted by rotating the adjusting knob I25.

The portion I28 of diaphragm I06 which covers the diaphragm chamber 92 is secured to a pin I29, which extends through a guide member I30 and is adapted for engagement with the member II5. A spring I3I is provided between the guide member I30 and the diaphragm portion I28 for urging this diaphragm portion and the pin I29 out. of engagement with the member II5 for thereby permitting the spring I21 to urge portion I26 into engagement with the daytime adjustingcam I24, However, when pressure is-applied to the diaphragm chamber 92 through pipe I32 which may lead to a. control panel, the force exerted against diaphragm portion I28 will overcome springs I'3I and I21 for thereby forcing the justing' cam I22. In doing so, it will be apparent "that the position of thermostatic element I I6 will be shifted .to the left and it will also be apparent that the .new position may be adjusted by rotating the night adjusting dial I23. If it is desired to. prevent the thermostat from assuming the 7 night position, a latch member I33 may be, providedior holding the member. II5 .against the portion-I26in'.engagement with the'da'y cam I24.

This latch'member I33 may be mounted upon a plication of this invention to a manually operated graduate switch. In this figure, reference character I50 indicates a base portion having a diaphragm chamber I5I and valve chambers I52 and I53 all of which are in communication as illustrated. The diaphragm chamber and the portion I26 into engagement with the night ad-.

' action of diaphragm portion I28 to retain the suitabldbracket I34 and may be actuated bymeans of a knob I35 which rotates the shaft I36 I upon' -wliich".the' latch member I 33 is mounted. Also, a spring I31 may-be provided for biasing the latchmember towards the neutral position so-that the thermostat will return to normal, control whenthe pressure applied to the diaphragm chamber 92 is reduced.

In operation, assuming an increase in-tem- .perature within the space, the bimetallic ele-- Y ment II6 will warp to the left thereby rocking.

the valve. lever I09 against the action of spring H3 and the pressure in diaphragm chamber 9|. This will open the air supply' valve 99 and thus admit air under pressure into the diaphragm 96, which pressure will be transmitted to the motor being controlled through passage I38 and pipe I39; As the pressure under diaphragm portion I I2 increases,';t his diaphragm portion, will be urged to the right thereby urging the valve lever" I09 and bimetallic element '6' to the neutral or intermediate position. It will be apparent that when the pressure under diaphragm I I2 balances the force of bimetallic element I I6, the valve lever I09 will assume the intermediate position 'at which the air supply valve 99' and the, vent valve I00 are both closed. It will also be apparent that upon a decrease in temperature, the bimetallic element II6 will move. to the right; thus permitchamber 5 as well as the valve chambers 95 and valve chambers are covered by a diaphragm I54 'just as in the other embodiments of this invention. Also the valve chambers I52 and I 53 are provided with valve members I55 and I56 which are arranged in exactly the same manner as the In this case,

valves in the other embodiments. the valve I 55 is a vent valve communicating with a vent passage I51 and the valve I56 is an air supply valve which communicates with a source of air under pressure through a passage I58. The valves are actuated through the diaphragm I54 by means of adjustable screws carried by the valve lever I59, this valve lever being actuated in part by the screw I60 which abuts the portion of dia-.-

phragm I54 covering the diaphragm chamber ISI. The diaphragm chamber I.5I also contains a spring I6I for biasing the diaphragm and lever arm in a direction tending to openthe vent valve I55. This diaphragm chamberis connected to the motor being controlled through passage I5Ia. The base member I50 is -mounted upon a bracket member I62 which is suitably secured tov a control panel I63. The bracket member I62 at its upper end is provided with a tubular portion.

I64 which extends through the panel board. I63 and which is provided with a nut I 65. The tubular portion I64 is internally threaded to receive I an adjusting screw- I66 to which is secured a ,handleI61 by means of a screw I68. The adjusting screw I66 through the screw I68 actuates a spring abutment member I69, 9. spring I10 extending between this member and. the valve lever I59. It will be apparent that by rotating the handle I61, the compression of spring I10 may be varied.

The operation of, this device is similar' 'to the operation of the thermostat described in Figures 6 and 7. Thus the pressure exerted against the diaphragm I54 is balanced bythe spring I10 and if this .pressure overcomes the spring, the valve lever I59'wil1 be rocked for opening the vent valve I55 for relieving pressure from the diaphragm chamber I5I and the device being con-- trolled until the force upon diaphragm 154 just, balances the spring I10, at which time both the supply and vent valves will .be closed. Conting the diaphragm portion H2 and spring II 3'to.

rock-valve lever I09 in a direction for opening the vent valve I00. This will decrease the pressure applied'to the motor being controlled and also the pressure under diaphragm portion II2. This decrease in the force opposing bimetallic element I I6 will cause the valve lever I09 to be returned to the neutral or' intermediate'posi tion when the pressure under diaphragm portion H2 just balances the force of element II6. It will be.

apparent thatby adjusting the position of abutversely, if the presure in diaphragm chamber I 5| is not sufficient to balance the spring I10,'

the lever I59 will be rocked for opening the supply valve I56 for admitting additional air to the diaphragm chamber and the device being conment member III in the slot II1, the operating trolled until the necessary pressure is obtained.

It is obvious that by adjusting the handle I61,

' the tension of spring I10 will be varied and consequently the pressure maintained .by the instrument may readily be varied. Y

Referring to Figure 9, this figure illustrates the application of the valve actuating arrangement to a snap acting three-way or diverting valve.

.In this figure, reference character I88 indicates the base portion having a diaphragm chamber I 8I, a valve chamber I82, and a valve chamber I88, these valve chambers being provided with valves I84 and I85. The diaphragm chamber I8I is provided with a'pipe connection I88. The

, valve chambers I82 and I83 are-in communication with each other and communicate through a passage I81 with a pipe connection I88. The

valve I84 controls air flow through a pipe connection I88, and the valve I85 controls air flow through a pipe connection I88.

As in thelcase of the other valves, the diaphragm chamber and the valve chambers are covered by a single diaphragm I8I and a lever arm I82 is provided for actuating the valves, In this case, a spring I83 is located between the diaphragm HI and the lever arm I82. Also, an adjustable spring I84 is provided between the lever I82 and the cap member I85, this spring being adjustable by an adjusting'screw I88 extending through the cap member. A snap action spring I81 is secured to a post I88 mounted upon the cover member I88, this spring fitting into a notch formed in the end of lever arm I82.

' This spring acts to prevent the lever arm' I82 from assuming the intermediate position at which. valve members I84 and I85 are both closed.

The lever arm I82 is also provided with stop screws 288 and.2III for limitingthe movement of this lever arm. I

vWhen the pressure applied to the diaphragm chamber I8I from the control instrument provides an upward force greater than the force exerted by spring I84, the lever arm I82 is rotated to the position shown in which the valve member I85 is disengaged from its .valve seat, thereby placing the pipe connection I88 in communication with the pipe connection I80. As the pressure in diaphragm chamber I8I is reduced, the spring I84 will eventually overcome the upward force of the diaphragm and thus cause rocking of the valve lever I82 in the counter-clockwise direction. When this movement is side of said pivot, means for biasing said valves towards closed position, means actuated by said lever arm for actuating said valves, said last named means causing both of said valves to remain closed when said lever arm is in intermediate position while opening one of said valves upon movement of said lever arm in one direction and opening the other of said valves upon movement of said lever arm in the opposite direction, sealing means comprising a yieldable diaphragm interposed between said valves and said actuating means for forming a chamber common to bothpf said valves, said chamber being connected to said motor, and yieldable means-connected between a movable portion of said motor and said lever arm for causing said lever arm to assume said intermediate position when the position of said movable portion corresponds to the pressure applied to said pressure responsive device.

2. -A positive positioning device for a pressure actuated motor. comprising in combination, a base portion associated in fixed relationship with the pressure actuated motor, said base portion including a diaphragm chamber and a valve chamber, a pair of valve ports in said valve chamber, a single diaphragm covering both said diaphragm chamber and said valve chamber, a pair of valve members associated with said valve ports so as to close the same upon movement of said valve members towards said diaphragm,

means for biasing said valve members towards I closed position, a lever arm pivoted in fixed relationship with said base portion and having its axis of rotation located between said valve ports, said lever arm actuating said valve members through said diaphragm in a manner to permit both of said valve members to close their respective ports when said lever arm is in intermediate position while moving one of said valve I members towards open position upon rotation of said lever arm in one direction and moving said I other valve memberv towards open position upon suilicient to cause the valve member I85 to ap proach its seat, the spring I81 snaps the valve lever over to its other position in which the valve member I84 is disengaged from its seat to place the pipe connection I88 into. communication with the pipe connection I88. While the spring I88 is not entirely necessary, this spring is desirable as it providesa resilient connection between the diaphragm and the valve lever, thereby allowing a slight amount of relative motion between the diaphragm and the valve lever for permitting the spring I81 to provide a more positive snap action. I

While I have shown and described only a few possible embodiments of my invention, it will be understood that it may be applied to still other types of controlsand that many ch'angesin design can be made without departing from the scope of the invention. I thereforedesire to be limited only by the scope of the appended claims.

I claim as my invention: r

1. A positive positioning device for a pressure actuated motor comprising in combination, a pressure responsive device to which a controlling pressure is applied, a lever arm having apivot,

said lever arm being actuated about said pivot of said valves being on one side of said pivot and the other of said valves being on the other rotation of said lever arm in the opposite direction, said valve chamber being connected to said motor whereby said valve members control the flow of actuating medium to and from said motor, means actuated by the portion of the diaphragm covering said diaphragm chamber for actuating said lever arm, and yieldable means actuated by the motor for causing said lever arm to assumesaid intermediate position when the position of said motor corresponds to the pressure applied to said diaphragm chamber.

3. A positive positioning device fora pressure actuated motor comprising in combination, a base portion associated in fixed relationship with the pressure actuated motor, said base portion including a diaphragm chamber and a valve chamber, a pair ofvalve ports in said valve chamber, diaphragm means covering said diaphragm chamber and said .valve chamber, a pair of valve members associated with said valve ports so as to close the same upon movement or said valve members towards said diaphragm means, means for biasing said valve members towards closed position, a lever arm pivoted in fixed relationship with said baseportioni'and having its axis of rotation located between said valve ports, said lever arm actuating said valve members through said diaphragm means in a manner to permit both of said valve members to close their respective ports when said lever arm is-in intermediate position while moving one of said valve members towards open position phragm chamber.

4. A fluid pressurecontrolling device of the character described, in combination, a base portion iormed to provide a diaphragm chamber and a valve chamber, a pair of valve ports in said valve chamber, a singlediaphragm covering both said diaphragm chamber and said valve chamber, a pair of valve members associated with said valve port's so as to close the same upon movement of said valve members towards said diaphragm, means for biasing said valve members towards closed position, a lever arm pivoted in fixed relationship with said base portion and having its axis of rotation located between said valve ports, said lever arm actuating said valve members through said diaphragm in a manner topermit both of said valve members to close their respective ports when the lever arm is in intermediate position while moving one of said valve members towards open position upon rotationof said lever arm in onedirection from said intermediate position and moving the other of said valve members towards open position upon movement of said lever arm in the opposite direction from said intermediate position, means actuated by the portion of said diaphragm covering said diaphragm chamber for actuating said lever arm, and yieldable means ior biasing said portion of said diaphragm in one direction.

5. A fluid pressure controlling device, of the character described, in combination, a base portion formed to provide a diaphragm. chamber a valve chamber, a pair of valve ports in said valve chamber, diaphragm means covering said diaphragm chamber and said valve chamber, a pair of valve members associated with said valve 'ports so as to close the same upon movement of said valve members towards the diaphragm means covering said valve chamber, means for biasing said valve members toward closed position, a lever arm pivoted in fixed relationship with said base portion and having its axis of rotation located between said valve ports, said lever arm actuating said valve members through the diaphragm means covering said valve chamber in a manner to permit both of said valve members to close their respective ports when said lever arm is in intermediate position while moving one of said valve members toward open posi-.

' that the diaphragm means covering'said dia and a valve chamber, a pair of valve ports in said valve chamber, diaphragm means covering said diaphragm chamber and said valve chamber,

a pair or valvemembers associated with said valve .'with said base-portion and having its axis of rotation iocated between said valve ports, said leverarm actuating said valvemembers through phragm chamber controls the pressure in said diaphragm chamber, and biasing means for determining the value of pressure maintained in said diaphragm chamber.

7. A fluid pressure controlling device of the character described, in combination, a base port1on formed to provide a diaphragm chamber and a valve chamber, a pair of valve portsnin said valve chamber, diaphragm means covering said diaphragm chamber and-said valve chamber, a pair of valvemembers associated with said valve ports so as to close the same upon movement of said valve 'members towards the diaphragm means covering said valve chamber, means for biasing said valve members toward closed position, a lever arm pivoted in fixed relationship with said base portion and having its axis of 1 rotation located between said valve ports, said lever arm actuating said valve members through the diaphragm means covering said-valve chamber in a manner'to permit both of said valve members to close their respective ports when said lever arm is in intermediate position while moving one of said valve members toward open position upon rotation of said lever arm in one direction from said intermediate position and t moving the other of said valve members toward open position upon movement of said lever arm in the opposite direction from said intermediate position, means actuated by the diaphragm means the diaphragm means covering said valve chamher in a manner to permit. both or said valve members to close their respective ports when said lever arm is in intermediate position while moving one of said valve members toward open position upon rotation of said lever arm in one direction from said intermediate position and tion formed to provide a diaphragm chamber and covering said diaphragm chamber for actuating said lever arm. said diaphragm chamber and said valve chamber being in communication so that the diaphragm means covering said diaphragm chamber controls the pressure in said diaphragm chamber, and biasing means for determining the value of pressure maintained in said diaphragm chamber, said biasing means comprising a condition responsive device which varies a biasing force in accordance with changes 1n value oi the condition to which the condition responsive device responds.

8. A fluid pressure controlling device of the character described, in combination, a base por- ,tion formed to provid a diaphragm chamber and a valve chamber, a pair oi valve ports in said valve chamber, diaphragm means covering said diaphragm chamber and said valve chamber, a pair of valve members associated with said valve ports so as to close the same upon move-;

.ment of said valve members towardsthe dia phragm means covering said valve chamber, means for biasing saidvalve members toward closed position, a lever arm pivoted in fixed'relationship with said base portion and having its 1 axis of rotation located between said valve ports,

said lever arm actuating said valve members through the diaphragm means covering said valve chamber in a manner to permit both of said valve members to close their respective ports when said lever arm is in intermediate position while moving one of said valve members toward open,

position upon rotation of said lever arm in one direction from said intermediate position and moving the other of said valve members toward .open position upon movement of said lever arm mining the value of pressure maintained in said diaphragm chamber, said biasing means comprising a condition responsive device which varies a biasing force in accordance with changes in value of the condition to which the condition responsive device responds, means for pivotally mounting said condition responsive device, stop means for limiting movement of said condition responsive device about its pivot in each direction, and a pressure actuated device for shifting said condition responsive device between said stop means. I

9. A fluid pressure controlling device of the character described, in combination, a base porby side in said base member, said valve chamber being adapted for connection to the motor and extending through said one side of the base member, an inlet valve port for said valve chamber, an outlet valve port for said valve, chamber, inlet and dutlet valve members associated with respective valve ports, said valve members and valve ports being arranged so that the valve ports are between said valve members and said one side of the base member, the valve members having operating means extending through said valve ports into said valve chamber, means for biasing said valve members against their seats, a lever pivoted between said valve members and extending substantially parallel with said base member to a point opposite said movable wall, said lever being actuated by said movable wall and actuating said valve operating means, sealthe valve ports are between the valve members tion formed topr'ovi'de a, diaphragm chamber and a valve chamber, a pair of valve ports in said valve chamber, diaphragm means covering said diaphragm chamber and said valve chamber, a pair of valve members associated with said valve ports so as to close the same upon movement of said valve members toward the diaphragm means covering said valve chamber, means for biasing ing means between said lever and said'valve operating means for sealing off said valve chamber, and afollow-up spring adapted to be actuated by the pressure actuated motor for cooperating with said diaphragm in positioning said lever.

11. A positive positioning device for a pressure actuated motor comprising, in combination, a base member adapted to-be associated in fixed relationship with the pressure actuated motor, said base member being recessed at one side to provide a control chamber and a valve chamber, said chambers being located side by side, said valve chamber being adapted for connection to the motor, an inlet valve port for said valve chamber, an outlet valve port for said valve chamber, inlet and outlet valve members associated with respective valve ports, said valve members and valve ports being arranged so that and said one side of the base member, the valve members having operating means extending through said valve ports into said valve chamber, means for biasing the valve members against their seats, diaphragm means coveringv said control chamber and said valve, chamber to provide a control diaphragm and a seal for said valve chamber, the. valve chamber seal formed by the diaphragm means engaging the operating means for the valve members, a lever pivoted between said valve members toward closed positi n, a

lever arm pivoted in fixed relationship wit said base portion and having its axis of rotation lo:- cated between-said valve ports, said lever arm actuating said valve members through the diaphragm means covering said valve chamber in a, manner to permit both of said valve members to close their respective ports when said leverarm is in intermediate position while moving one of said valve members toward open position upon rotation of 'said'lever arm in one direction from said intermediate position and moving the other of said'valve members toward open position upon movement of .said lever arm in the opposite direction from said intermediate position, means actuated by the diaphragm means covering said diaphragm chamber for actuating said lever arm, and snap acting means for preventing said said' valve members and extending generally parallel to the base member to a point opposite the control diaphragm, said lever being actuated by said control diaphragm and actuating said valve operating means through said valve chamber seal, and a follow-up spring adapted to be actuated by the pressure-actuated motor for cooperating with said control dia hragm in po-' sitioning said lever.

lever means from remaining in said intermediate position.

10. A positive positioning device for a pressure actuated motor comprising, in combination, a base member adapted to be associated lnfixed relationship with the pressure actuated motor, means providing a control chamber having a movable wall at oneside of the base member, a valve chamber, said chambers being located side- 12; A' pneumatic control device comprising in combination, a base member, said base member being recessed at one side to provide a control chamber and a valve chamber, said chambers being located side by side, an inlet valve port for said valve chamber, an outlet valve-port for said valve chamber, inlet and outlet valve members associated with respective valve ports, said valve members and valve ports being arranged so that the valve ports arebetween the valve members and said one side of the base member, the valve members having operating means extending through said valve ports into said valve chamber, means for biasing the valve members against their seats, diaphragm means covering said control chamber and said valve chamber to provide a control diaphragm and a seal for said valve chamber, the valve chamber seal engaging the'operating means for the valve members, and p a lever pivoted between said valve members and extending generally parallel to the base member to a point opposite the control diaphragm,

being located side by side, an inlet valve port for said valve chamber, an outlet valve port for said valve chamber, inlet and outlet valve members associated with respective valve ports, said valve members and valve ports being arranged so that thevalve ports are between the valve members and said one side of the base member, the valve members having operating means extending through said valve ports into said valve-chamber, means for biasing the valve members against their seats, diaphragm means covering" .said control chamber and said valve chamber to provide a control diaphragm and a seal for said valve chamber, the valve chamber seal engaging the operating means for, the valve members, a plate member for securing, said diaphragm means in place, said plate member having an opening coinciding with said control chamber and an opening adjacent said valve chamber, a lever pivoted to said plate member at a point hetweenv said valve members and having means actuating the valve operating means through the valve chamber seal, said lever extending generally parallel to said plate member to a point opposite the control diaphragm and being actuated thereby.

14. In a three-way valve device, in combination, a base having a recess therein and a substantially flat surface surrounding said recess, a

normally flat diaphragm carried against the flat portion of said base and extending over the recess "for forming a pressure tight chamber between said base and said diaphragm, first and second valve members biased toward said diaphragm to engage a pair of valve seats in said base, said valve members having portions extending into the recess for engagement by said diaphragm, an operating lever having a pivot between said valve members, said lever and pivot being located outside the chamber formed by said diaphragm and said base, and valve actuating means carried by said lever, said actuating means comprising a pair of abutments extending to points directlyacross said diaphragm from the portions of said valve members which extend into the recess in said base, at least one of said abutments being adjustable with respect to said lever for adjusting the movement of said lever necessary to move said first valve member from its seat after said second valve member has i 

